In the period February 1984-March 1985, 26 confirmed cases of
tuberculosis (TB) were reported among homeless people in Boston
(Figure 1). All 26 cases have been associated with three large
shelters. The estimated total population of homeless people in
Boston
is 6,000. Nineteen of the 26 cases were counted in 1984; this
represents an incidence of 316.7 per 100,000, a greater than
sixfold
increase over the 1983 case rate of approximately 50.0/100,000. By
comparison, the TB case rate for the rest of Boston in 1984 was
19.0/100,000, and the rate for Massachusetts excluding Boston was
4.8/100,000.

The outbreak was recognized because of reports among the
homeless
of a number of TB cases due to multiresistant organisms. As a
result
of this recognition, a screening program using Mantoux tuberculin
skin
tests, chest roentgenograms, and sputum examinations was
implemented
in November 1984. The program was carried out during a 4-night
period
in Boston's three largest shelters--those associated with the
present
outbreak. An average of 754 persons stayed at the three shelters
on
each screening night; all who agreed were screened. Chest x-rays
were
obtained for 438 persons; sputum was obtained from 274 for
microscopic
examination and culture. Skin tests were done on 350 people; 185
(52.9%) returned for reading, and of these, 34 (18.4%) had a 10-mm
or
larger reaction. As a result of the screening, five of the 26 TB
cases were detected.

Other case-finding/control measures have included educational
outreach efforts for the staffs of all Boston shelters, with an
emphasis on rapid medical referral of clients presenting with a
clinical picture suggesting TB. Two of the 26 individuals with TB
were identified by this method after the screening in November.

Of the 26 TB patients, one is hospitalized, two have died, one
has
moved out of the state, and 22 are under outpatient treatment.
Thirteen of these 22 are on directly observed therapy (drug
ingestion
observed by a health-care provider).

To date, sputum cultures from 23 of the 26 homeless patients
have
been bacteriologically confirmed as containing Mycobacterium
tuberculosis. Fourteen (60.9%) of the 23 patients had organisms
that
were resistant to both isoniazid (INH) and streptomycin (SM); all
14
of these persons had spent time at the same shelter. One
additional
patient had organisms resistant to INH only, and another had
organisms
resistant to ethambutol (EMB) only.

Isolates from 21 of the 23 bacteriologically proven cases among
the homeless and 13 control cultures from Boston residents not
known
to be associated with the outbreak have been phage typed at CDC.
Thirteen isolates from the homeless were phage type 8
(7,9,12,13,14,15). Eleven of these were resistant to INH and SM,
and
one was resistant to EMB; one was susceptible to all drugs tested.
Only one of the 13 control cultures was resistant to INH and SM and
of
the outbreak phage type. The individual from whom this culture was
obtained denies any association with the homeless population.

Two individuals are suspected sources for the other cases with
INH- and SM-resistant bacilli of the outbreak phage type. One,
diagnosed in December 1983, was a 33-year-old man with a history of
alcohol abuse who frequented a 350-bed Boston shelter. He had had
a
significant tuberculin skin-test reaction in 1973. He had twice
begun
preventive therapy but had not continued for more than a total of 2
months. In December 1983, a chest roentgenogram revealed extensive
bilateral cavitary disease, and sputum smears contained many
acid-fast
bacilli (AFB). A second possible source, a 57-year-old man with
schizophrenia, had a history of TB previously treated in 1980.
Sputum
cultures were negative; the diagnosis was clinically established.
He
was hospitalized and treated with multiple drug regimens that
initially included INH, SM, and rifampin (RIF). He completed 2
months
of inpatient therapy, and a total of 14 months of biweekly and then
daily supervised therapy as an outpatient. He showed
roentgenographic
and clinical improvement. In July 1984, he presented with cough
and a
new infiltrate on his chest roentgenogram; sputum smears contained
many AFB.

A voluntary program of active surveillance for clients and
staff
using skin testing alone is being introduced in all Boston
shelters;
to date, 13 of the 84 staff members tested at the 350-bed shelter
have
had tuberculin skin-test conversions. Preventive therapy with
either
RIF alone or INH and RIF is being recommended for these
individuals.
Reported by J Bernardo, MD, Boston City Hospital, Boston University
School of Medicine, E Brigandi, B Blakeney, B McInnis, B Richards,
Health Care for the Homeless, Boston, C Wall, L Shirley, MA Barry,
MD,
Boston Department of Health and Hospitals, T Kearns, S Weidhaas, B
Thomas, E Nardell, MD, Div of Tuberculosis Control, DL Johnson,
Mycobacteriology Laboratory, Massachusetts Department of Public
Health; Div of Bacterial Diseases, Center for Infectious Diseases,
Div
of Tuberculosis Control, Center for Prevention Svcs, CDC.

Editorial Note

Editorial Note: High rates of TB in homeless populations have been
noted previously (1), although a large outbreak such as the one
reported here has not been previously documented. A high incidence
of
disease in this population is not unexpected because TB case rates
are
higher in lower socioeconomic groups (2). Furthermore, stress,
alcoholism, drug addiction, and low body weight, which are probably
more common among the homeless, have been reported to increase the
risk of TB (3-6). While shelters for the homeless are vital, this
outbreak points out the potential danger of transmission of TB when
large numbers of homeless persons come together.

Outbreaks of TB can be difficult to detect because of the
relatively long and variable incubation period of the disease. In
this outbreak the drug-resistance patterns of tubercle bacilli
served
as a marker for the recognition of the outbreak. If an outbreak is
suspected among patients with drug-susceptible organisms, phage
typing
of cultures may be helpful.

Screening and follow-up is difficult in a transient population.
The use of incentives, such as food and food vouchers, has been
reported to enhance compliance with screening and drug therapy
(7,8).
Shelter employees should learn the signs and symptoms of TB and
refer
shelter clients with these signs and symptoms for an examination.
For
those with TB, outpatient treatment using directly observed therapy
on
a daily or twice weekly basis to ensure compliance is likely to be
more cost effective than long-term hospitalization. Directly
observed
therapy for noncompliant and potentially noncompliant patients is
important to prevent treatment failure, perhaps with the emergence
of
resistance to additional drugs, and to prevent continued
transmission
of infection.

Transmission of INH-resistant organisms to contacts presents a
difficult problem with regard to preventive therapy. The only drug
of
proven value in preventing tuberculosis is INH. Because of the
high
probability that shelter employees with tuberculin-skin-test
conversions were infected with INH-resistant organisms, preventive
therapy with a regimen including RIF was used. Although the
efficacy
of preventive treatment with RIF has not been demonstrated in
controlled trials, the results of a survey of TB experts to
determine
the choice of preventive treatment for INH-resistant TB infection
support the use of RIF (9).

Staff of shelters for the homeless should receive a tuberculin
skin test upon employment and every 6-12 months thereafter.
Skin-test
converters should be considered for preventive therapy according to
current guidelines (10).

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